US4229423A - Method of producing magnesium hydroxide - Google Patents

Method of producing magnesium hydroxide Download PDF

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Publication number
US4229423A
US4229423A US06/010,577 US1057779A US4229423A US 4229423 A US4229423 A US 4229423A US 1057779 A US1057779 A US 1057779A US 4229423 A US4229423 A US 4229423A
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United States
Prior art keywords
magnesium hydroxide
brine
lime
content
reaction stage
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Expired - Lifetime
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US06/010,577
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English (en)
Inventor
Lloyd M. Housh
William R. Alder
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NATIONAL REFRACTORIES & MINERALS Corp A CORP OF
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Kaiser Aluminum and Chemical Corp
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Priority to US06/010,577 priority Critical patent/US4229423A/en
Priority to IE239/80A priority patent/IE49386B1/en
Priority to JP1376180A priority patent/JPS55109221A/ja
Priority to GB8004329A priority patent/GB2049640B/en
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Publication of US4229423A publication Critical patent/US4229423A/en
Assigned to NATIONAL REFRACTORIES & MINERALS CORPORATION, A CORP OF CA reassignment NATIONAL REFRACTORIES & MINERALS CORPORATION, A CORP OF CA ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: KAISER ALUMINUM & CHEMICAL CORPORATION
Assigned to ITT INDUSTRIAL CREDIT COMPANY, A NV CORP. reassignment ITT INDUSTRIAL CREDIT COMPANY, A NV CORP. SECURITY INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: NATIONAL REFRACTORIES & MINERALS CORPORATION
Assigned to CONGRESS FINANCIAL CORPORATION, A CA CORP. reassignment CONGRESS FINANCIAL CORPORATION, A CA CORP. SECURITY INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: NATIONAL REFRACTORIES & MINERALS CORPORATION
Assigned to NATIONAL BANK OF CANADA, A CANADIAN BANKING CORP. reassignment NATIONAL BANK OF CANADA, A CANADIAN BANKING CORP. SECURITY INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: NATIONAL REFRACTORIES & MINERALS CORPORATION
Assigned to NATIONAL REFRACTORIES & MINERALS CORPORATION, A CORP. OF CA reassignment NATIONAL REFRACTORIES & MINERALS CORPORATION, A CORP. OF CA RELEASED BY SECURED PARTY (SEE DOCUMENT FOR DETAILS). Assignors: ITT COMMERICIAL FINANCE CORP.
Assigned to CITICORP NORTH AMERICA, INC., A CORP. OF DE reassignment CITICORP NORTH AMERICA, INC., A CORP. OF DE SECURITY INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: NATIONAL REFRACTORIES & MINERALS CORPORATION
Assigned to NATIONAL REFRACTORIES & MINERALS CORPORATION reassignment NATIONAL REFRACTORIES & MINERALS CORPORATION RELEASED BY SECURED PARTY (SEE DOCUMENT FOR DETAILS). Assignors: ITT COMMERCIAL FINANCE CORPORATION
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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
    • C01F5/00—Compounds of magnesium
    • C01F5/14—Magnesium hydroxide
    • C01F5/22—Magnesium hydroxide from magnesium compounds with alkali hydroxides or alkaline- earth oxides or hydroxides

Definitions

  • This invention concerns a method of producing magnesium hydroxide by reacting lime (CaO) with brine containing Mg ++ ions and over 1 ppm boron (on a B 2 O 3 basis) wherein an excess of lime is reacted with the brine in a first reaction stage, and the high lime magnesium hydroxide is reacted with further brine in a second reaction stage.
  • lime CaO
  • magnesium hydroxide Although there are many uses for magnesium hydroxide, one important one is as a raw material for producing refractory grain containing over 90%, and preferably over 95%, MgO.
  • the production of such periclase refractory grain from magnesium hydroxide produced by reacting a brine containing magnesium ion with active lime has been practiced for many years (see Br. Pat. No. 1,502,422), and it is well-known that the properties of the refractory grain are highly dependent on the type and amount of impurities in the material.
  • refractory grain One of the important properties of refractory grain is its density. It is desirable to have a periclase grain with a bulk specific gravity (BSG) of at least 3.35, and preferably of at least 3.40. Again, it has been found that the relative amounts of the minor impurities in magnesium hydroxide used to produce periclase grain greatly affect the sintered density of the grain.
  • BSG bulk specific gravity
  • the BSG of the grain will be considerably lower (e.g., 3.25 as opposed to 3.4 or greater) than that of a grain similarly processed but using a magnesium hydroxide which contains only 0.05% B 2 O 3 to begin with.
  • a magnesium hydroxide which contains only 0.05% B 2 O 3 to begin with.
  • such a magnesium hydroxide can be produced by (1) treating a brine containing Mg ++ ions and at least 1 ppm boron (on a B 2 O 3 basis) so as to reduce its CO 2 content to less than 15 ppm, (2) reacting the treated brine with an excess of calcined lime in a first reaction stage, (3) separating the high-lime magnesium hydroxide so produced from the spent brine, (4) recycling part of the high-lime magnesium hydroxide from the first reaction stage back to the first reaction stage as seed, and (5) reacting the remainder of the high-lime magnesium hydroxide produced in the first reaction stage with further treated brine in a second reaction stage, whereby a magnesium hydroxide is produced which contains, on the ignited basis, less than 1% CaO and less than 0.1% B 2 O 3 , all percentages being by weight.
  • the drawing represents a flow sheet of the process of the present invention, including certain optional but advantageous additional steps.
  • the brine used in this invention will be any brine with a boron content sufficiently high that the resulting magnesium hydroxide would otherwise contain more boron than desired. While the exact value of this level will vary somewhat for different precipitation processes (since different processes may cause different fractions of the boron present in the brine to be present in the precipitated magnesium hydroxide), generally speaking the process of this invention will be useful with any brine containing over 1 ppm boron (on a B 2 O 3 basis).
  • a common source of brine in this general process is sea water, although very often the process is operated with inland brines. It is essential that the brine be treated to reduce its CO 2 content to less than 15 ppm, preferably to about 10 ppm or less.
  • the CO 2 content of the brine is determined by adding to it methyl orange-xylene cyanole indicator (producing a pale green color) and titrating with H 2 SO 4 until the green color changes to pale yellow or colorless.
  • methyl orange-xylene cyanole indicator producing a pale green color
  • H 2 SO 4 titrating with H 2 SO 4 until the green color changes to pale yellow or colorless.
  • the active lime used may be any such material, various ones such as calcined limestone, calcined oyster shells, and the like being well known.
  • a particularly advantageous material is calcined dolomite, sometimes referred to as "dolime". Since dolomite is roughly half magnesium carbonate, yielding magnesium oxide when calcined, the magnesium values from the dolomite are added to those from the brine to produce a larger amount of magnesium hydroxide.
  • active lime is used in the specification and claims, it is intended to include materials such as dolime, as well as active lime (CaO) per se.
  • the active lime and treated brine are mixed together in a first stage or primary or overlime reactor where there is vigorous agitation. Also fed to the primary reactor is "seed" material which is magnesium hydroxide produced in this primary or overlime reactor. As is known in this art, from 80 to 95% or perhaps slightly more of the magnesium hydroxide produced is recycled as seed.
  • the overflow from the overlime reactor containing spent brine (i.e., brine from which the Mg ++ ions have been removed) and the precipitated magnesium hydroxide (together with any magnesium hydroxide brought in when dolime is the source of active lime) goes to a settler, where flocculant can be added to assist in settling.
  • the resulting precipitate is a magnesium hydroxide containing relatively low boron (e.g., less than 0.1%) but a relatively high amount of CaO (e.g., over 1%, for example about 2%). It is this material which is used as seed in the primary or overlime reactor.
  • this low boron, high lime magnesium hydroxide can be washed and filtered to produce a magnesium hydroxide suitable for producing certain types of refractory grain.
  • this side stream is not an essential part of the present invention, and its use is merely an added advantage of the present process.
  • the spent brine is removed from the top of the settler and reacted with treated brine in an effluent reactor to precipitate a magnesium hydroxide of high boron and relatively high lime content.
  • the magnesium hydroxide produced in this side reaction may also be useful for producing certain grades of periclase refractory grain.
  • the main reason for treating the spent brine from the settler is that, due to the excess lime in the primary reactor, its pH is relatively high (over 11 and possibly as high as 13) and it is necessary to reduce its pH before it may be discarded, for example by returning sea water to the ocean.
  • this side reaction recovers a significant portion of the magnesium values in the treated brine reacted with the spent brine.
  • the portion of the magnesium hydroxide removed from the settler which is not returned to the primary reactor as seed is fed to a second stage or back reactor where it is reacted with further treated brine to reduce the excess lime, producing soluble Ca ++ ions and more magnesium hydroxide.
  • the slurry from this second stage reactor is then washed and filtered to produce the low boron, low lime magnesium hydroxide sought by the process of this invention.
  • the seed used in the primary reactor is the low boron, but high lime, magnesium hydroxide produced in the primary reaction, and is not the final low boron, low lime product. It has been found that when the final product of the process is used as seed in the primary reactor, and the decantation between the primary reactor and the back reactor is omitted, then the desired low lime and low boron contents are not obtained. The reason for this is not certain, and it is not desired to be bound to any particular theory; however, it is believed that in order to prevent boron from attaching to the magnesium hydroxide flocks formed in the primary reactor, it is essential to have not only excess lime in the reaction chamber, but also a seed of high lime content. Apparently boron will not deposit on the surface of such high lime material, but will deposit on seed of lower lime content.
  • Sea water from the Pacific Ocean in the vicinity of Moss Landing, California, containing 15 ppm B 2 O 3 and 2.1 g/L MgO in the form of Mg ++ ion was treated with sulfuric acid (at a rate of 0.14 g of acid per liter of sea water) to reduce the CO 2 content to about 10 ppm and fed, at a temperature of 16° C. (60° F.) and a rate of about 2500 mL per minute, to a seed pot where it was admixed with magnesium hydroxide seed.
  • the sea water and seed were fed to the first of three chambers constituting the primary reactor where they were mixed with calcined dolomite from Natividad, California, under 2.37 mm in size (i.e., minus 8 mesh) at the rate of about 15 g/min.
  • the reaction admixture passed in series through the three chambers of the primary reactor, there being vigorous agitation in the first two and more gentle agitation in the third.
  • the overflow from the primary reactor (about 2890 mL/min) was mixed with flocculant (brand name Nalco 8873) at a rate of about 0.014 g/min, and fed to the settler.
  • the underflow from the settler was divided into two streams, the larger, about 390 mL/min being recycled to the seed pot and the smaller, about 55 mL/min, being sent to the back or secondary reactor tank, where it was mixed with more acid treated sea water, about 300 mL/min.
  • Control of the amount of dolime added to the primary reactor and of treated sea water added to the secondary reactor was primarily based on pH.
  • the amount of dolime added in the primary reactor was sufficient to raise the pH in that reactor to about 11 or more, whereas the amount of sea water added in the secondary reactor was sufficient to lower the pH to about 10.
  • the product from the secondary reactor was washed, filtered, and dried. When examined under a transmission electron microscope, it was found to have a blocky morphology. Further treatment and testing are described below.
  • Sediment from the bottom of the third chamber of the primary reactor was removed and separated into two streams.
  • the larger, about 170 mL/min, was recycled to the seed pot, while the smaller, about 70 mL/min, was fed to a tank where it was slurried with acid treated sea water.
  • the overflow from this tank, containing the finest particles, was fed to the seed pot, while the underflow, containing coarser particles, was fed to a classifier.
  • the coarser particles from the classifier were fed to a screen, the material passing over the screen, of coarser particle size and largely consisting of silicates, being sent to waste and the material passing through the screen being returned to the tank.
  • the high pH effluent from the settler was treated with sufficient acid treated sea water to lower its pH to 10.7, thus precipitating a high boron, high lime magnesium hydroxide. After this magnesium hydroxide was settled out, the effluent was discharged to waste.
  • the system just described was operated, but without any settling and decantation between the primary or overlime reactor and the secondary or back reactor, and the seed in this comparison test was supplied from the final product of the system.
  • the seed was a relatively low lime, rather than a high lime, magnesium hydroxide.
  • Table I sets forth the analyses of B 2 O 3 , CaO, and SiO 2 in the magnesium hydroxide (A) produced in the above example, the high lime magnesium hydroxide (B) removed from the first settler, and the product of the comparison example (C) wherein the decantation was omitted and the seed used was the final product. These analyses were made after washing the hydroxide. It can be seen that the product of this invention had less than 0.1% B 2 O 3 and less than 1% CaO. As would be expected, the high lime intermediate product (2.07% CaO) also had low boron. However, the product produced in the comparison reaction, while it had less than 1% CaO, had 0.27% B 2 O 3 , a much higher amount than desired.
  • each of the three magnesium hydroxides was, in the wet filter cake condition, blended with sufficient ball milled chrome ore to provide 0.2% Cr 2 O 3 (ignited basis). Also, the SiO 2 content of the high lime intermediate product was increased to 0.7% to reduce the lime-silica ratio to a value nearer 2:1. After drying, each was subjected to a sintering test by first calcining at 1000° C., then compacting into briquettes at a pressure of 3800 kg/cm 2 (54,000 psi), and firing a small rotary kiln about 1 m in diameter by 1 m in length,
  • Each of the three sets of briquettes was separately fired to a temperature of 1900° C., being held at that temperature for 30 minutes.
  • Table I sets forth the B 2 O 3 , CaO, and SiO 2 contents of these fired briquettes, together with their BSG's and corresponding porosity (in volume percent).

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Inorganic Chemistry (AREA)
  • Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
  • Compositions Of Oxide Ceramics (AREA)
US06/010,577 1979-02-09 1979-02-09 Method of producing magnesium hydroxide Expired - Lifetime US4229423A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
US06/010,577 US4229423A (en) 1979-02-09 1979-02-09 Method of producing magnesium hydroxide
IE239/80A IE49386B1 (en) 1979-02-09 1980-02-07 Method of producing magnesium hydroxide
JP1376180A JPS55109221A (en) 1979-02-09 1980-02-08 Method of making magnesium hydroxide
GB8004329A GB2049640B (en) 1979-02-09 1980-02-08 Magnesium hydroxide

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US06/010,577 US4229423A (en) 1979-02-09 1979-02-09 Method of producing magnesium hydroxide

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US4229423A true US4229423A (en) 1980-10-21

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US (1) US4229423A (enrdf_load_stackoverflow)
JP (1) JPS55109221A (enrdf_load_stackoverflow)
GB (1) GB2049640B (enrdf_load_stackoverflow)
IE (1) IE49386B1 (enrdf_load_stackoverflow)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4378341A (en) * 1980-05-05 1983-03-29 Hoechst Aktiengesellschaft Process for the manufacture of ammonium nitrilotrisulfonate
US4497781A (en) * 1981-11-17 1985-02-05 Steetley Refractories Limited Manufacture of magnesium hydroxide
US20050127001A1 (en) * 2002-03-25 2005-06-16 Johannes Lindemann Method and device for producing a metal hydroxide
US20070191214A1 (en) * 2006-01-31 2007-08-16 Pushpito Kumar Ghosh Process for the preparation of magnesia (MgO) from crude Mg (OH)2

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02275715A (ja) * 1983-04-12 1990-11-09 Ube Chem Ind Co Ltd 高純度水酸化マグネシウムの製造法

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2573616A (en) * 1939-12-03 1951-10-30 Seailles Jean Charles Methods of extracting magnesia from aqueous solution containing magnesium salts decomposable by lime and alkalies
US2595314A (en) * 1948-10-19 1952-05-06 Kaiser Aluminium Chem Corp Process for producing magnesium hydroxide
US2692816A (en) * 1952-04-11 1954-10-26 Kaiser Aluminium Chem Corp Process for preparing magnesium hydroxide
US2893840A (en) * 1955-12-15 1959-07-07 Kaiser Aluminium Chem Corp Production of magnesium compound
US3425804A (en) * 1966-03-01 1969-02-04 Dresser Ind Production of magnesium hydroxide from aqueous solutions containing magnesium and boron values
US3787558A (en) * 1969-10-17 1974-01-22 Steetley Mfg Ltd Magnesium hydroxide production
GB1413871A (en) 1973-01-05 1975-11-12 Shin Nihon Kagaku Kogyo Kk Method of producing magnesia refractory grains
GB1502422A (en) 1975-03-06 1978-03-01 Steetley Minerals Ltd Process for making magnesium hydroxide

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS494638A (enrdf_load_stackoverflow) * 1972-05-08 1974-01-16
JPS5819608B2 (ja) * 1973-07-28 1983-04-19 新日本化学工業株式会社 水酸化マグネシウムの製造方法
JPS6411569A (en) * 1987-07-06 1989-01-17 Nittan Co Ltd Foam fire extinguishing agent mixing apparatus

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2573616A (en) * 1939-12-03 1951-10-30 Seailles Jean Charles Methods of extracting magnesia from aqueous solution containing magnesium salts decomposable by lime and alkalies
US2595314A (en) * 1948-10-19 1952-05-06 Kaiser Aluminium Chem Corp Process for producing magnesium hydroxide
US2692816A (en) * 1952-04-11 1954-10-26 Kaiser Aluminium Chem Corp Process for preparing magnesium hydroxide
US2893840A (en) * 1955-12-15 1959-07-07 Kaiser Aluminium Chem Corp Production of magnesium compound
US3425804A (en) * 1966-03-01 1969-02-04 Dresser Ind Production of magnesium hydroxide from aqueous solutions containing magnesium and boron values
US3787558A (en) * 1969-10-17 1974-01-22 Steetley Mfg Ltd Magnesium hydroxide production
GB1413871A (en) 1973-01-05 1975-11-12 Shin Nihon Kagaku Kogyo Kk Method of producing magnesia refractory grains
GB1502422A (en) 1975-03-06 1978-03-01 Steetley Minerals Ltd Process for making magnesium hydroxide

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4378341A (en) * 1980-05-05 1983-03-29 Hoechst Aktiengesellschaft Process for the manufacture of ammonium nitrilotrisulfonate
US4497781A (en) * 1981-11-17 1985-02-05 Steetley Refractories Limited Manufacture of magnesium hydroxide
US20050127001A1 (en) * 2002-03-25 2005-06-16 Johannes Lindemann Method and device for producing a metal hydroxide
US7282188B2 (en) * 2002-03-25 2007-10-16 Imb + Frings Watersystems Gmbh Method and device for producing a metal hydroxide
US20070191214A1 (en) * 2006-01-31 2007-08-16 Pushpito Kumar Ghosh Process for the preparation of magnesia (MgO) from crude Mg (OH)2
US7771682B2 (en) * 2006-01-31 2010-08-10 Council Of Scientific And Industrial Research Process for the preparation of magnesia (MgO) from crude Mg (OH)2

Also Published As

Publication number Publication date
IE800239L (en) 1980-08-09
GB2049640A (en) 1980-12-31
GB2049640B (en) 1982-11-24
IE49386B1 (en) 1985-10-02
JPS55109221A (en) 1980-08-22
JPS6411569B2 (enrdf_load_stackoverflow) 1989-02-27

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